Natural and Engineered Resistance to Plant Viruses (eBook)

Front Cover 1
Advances in Virus Research 4
Copyright Page 5
Contents 6
Preface 8
Chapter 1: The Coevolution of Plants and Viruses: Resistance and Pathogenicity 10
I. Introduction 12
II. Virus Infection and Host Defenses Reciprocally Affect the Fitness of Host and Virus 13
III. The Outcome of Plant-Virus Interactions Depends on the Plant and Virus Genotypes Involved 15
IV. Genetic Variation of Resistance and Pathogenicity 22
A. Variability of resistance and pathogenicity under the gene-for-gene model 23
B. Variability of resistance and pathogenicity under the matching-allele model 27
V. Costs of Pathogenicity and Resistance Durability 29
VI. Concluding Remarks 32
Acknowledgments 33
References 33
Chapter 2: Assessment of the Benefits and Risks for Engineered Virus Resistance 42
I. Introduction 43
II. The Cost of Plant-Virus Infection 44
III. Antiviral Strategies Not Based on Genetic Engineering 45
A. Naturally occurring virus-resistance genes 45
B. Agricultural practices 45
C. Cross-protection 46
IV. Transgene-Mediated Resistance 47
V. Refinements to Engineering Resistance 48
A. Further developments of pathogen-derived resistance 48
B. Virus-resistance transgenes without viral sequences 50
VI. Concepts of Risk Assessment 51
VII. Potential Risks Associated with Virus-Resistant Transgenic Plants 52
A. Potential food safety issues 52
B. Potential impact on the environment 53
VIII. Weighing the Benefits and Risks. Taking into Account Efficacy, Durability, and Safety 55
A. Time required 56
B. Cost 56
C. Breadth and efficacy of resistance 56
D. Durability 57
IX. Conclusions 57
References 58
Chapter 3: Signaling in Induced Resistance 66
I. What is Induced Resistance? 68
II. Signaling in Genetically Determined Resistance 69
A. Resistance conditioned by recessive, semidominant, and multiple genes 69
B. Resistance conditioned by dominant resistance (R) genes 70
III. Low Molecular Weight Chemical Signals in Induced Resistance 73
A. The biosynthesis and occurrence of salicylic acid and its derivatives, during incompatible and compatible interactions with viruses 73
B. Signaling mediated by ethylene and jasmonates 75
C. Long-distance signaling in SAR induction: A perennial conundrum 76
D. Signaling by reactive oxygen, calcium, and nitric oxide 78
E. Novel signals in defense against viruses and other pathogens 79
IV. RNA Silencing and Induced Resistance 81
A. RNA silencing 81
B. Connections between RNA silencing and induced resistance 89
C. Jasmonic acid and RNA silencing: Implications for virus transmission 92
V. Protein Factors in Signaling or Resistance Responses 93
A. Resistance gene products 95
B. Early signaling factors 99
C. Transcription factors 103
D. Host effector proteins 107
VI. Concluding Thoughts 111
Acknowledgments 112
References 112
Chapter 4: Global Genomics and Proteomics Approaches to Identify Host Factors as Targets to Induce Resistance Against Tomato Bushy Stunt Virus 132
I. Introduction 134
A. (+)RNA virus replication is a multistep process in the infected cells 135
B. Selection of the viral RNA template for replication and the recruitment of the replication proteins to the subcellular sites of replication 135
C. The assembly of the replicase complexes of (+)RNA viruses is a complex process 137
D. RNA synthesis by the viral replicase is a two-step process 137
E. Tombusviruses are simple model (+)RNA viruses of plants 138
II. Genome-Wide Screens for Systematic Identification of Host Factors Affecting TBSV Replication 139
A. Single-gene-knockout YKO library 140
B. yTHC library/essential genes 141
III. Proteomics-Based Screens for Systematic Identification of Host Factors Affecting TBSV Replication 142
A. Replicase purification/mass spectrometry 143
B. A yeast protein microarray approach to identify host proteins interacting with the viral replication proteins 143
C. A yeast protein microarray approach to identify host proteins binding to the viral RNA 145
IV. Grouping of Host Factors and Identification of Networks Involved in TBSV Replication 146
A. Translation factors and cellular proteins involved in protein biosynthesis 147
B. Protein modification enzymes 149
C. RNA-binding proteins, RNA modification enzymes, and proteins involved in RNA metabolism 164
D. Proteins involved in lipid/membrane biosynthesis and metabolism 167
E. Cellular proteins involved in vesicle-mediated transport/intracellular protein targeting 168
F. Membrane-associated cellular proteins 170
G. Proteins with stress-related functions 171
H. Proteins involved in general metabolism of the cell 172
I. Cellular transcription factors 174
J. Cellular proteins involved in DNA remodeling/metabolism 174
K. Cellular and hypothetical proteins with unknown functions 174
L. Host factors missed during the global genomics and proteomics screens 175
V. Validation of Host Factors in a Plant Host and Induction of Resistance Against TBSV 176
VI. Summary and Outlook 177
Acknowledgments 178
References 178
Chapter 5: Resistance to Aphid Vectors of Virus Disease 188
I. Resistance to Aphids 189
II. Natural Resistance 190
A. Basal resistance 190
B. R gene-mediated aphid resistance 197
C. Indirect resistance and extrinsic factors 201
III. Engineered Resistance 204
A. Breeding for resistance 204
B. Transgenic resistance 206
IV. Concluding Remarks 207
Acknowledgments 210
References 210
Chapter 6: Cross-Protection: A Centuryof Mystery 220
I. Introduction 221
II. General Remarks 222
A. Definition of cross-protection 222
B. Properties of mild strains 223
C. Disadvantages of cross-protection 223
III. History of Cross-Protection 224
IV. Applications 227
A. ZYMV 227
B. PRSV 229
C. CTV 232
V. Mechanism(s) of Cross-Protection 236
A. Early explanations 236
B. Lessons from pathogen-derived resistance 238
C. RNA silencing and cross-protection 240
D. Exclusion/spatial separation 245
VI. Protection Phenomena Involving Subviral Agents 247
A. Satellite viruses 248
B. Satellite RNAs 248
VII. Concluding Thoughts 251
Acknowledgments 253
References 253
Index 274
Color Plates 279